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Jablonowski CM, Gil HJ, Pinto EM, Pichavaram P, Fleming AM, Clay MR, Hu D, Morton CL, Pruett-Miller SM, Hansen BS, Chen X, Jones KMD, Liu Y, Ma X, Yang J, Davidoff AM, Zambetti GP, Murphy AJ. TERT Expression in Wilms Tumor Is Regulated by Promoter Mutation or Hypermethylation, WT1, and N-MYC. Cancers (Basel) 2022; 14:cancers14071655. [PMID: 35406427 PMCID: PMC8996936 DOI: 10.3390/cancers14071655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/08/2022] [Accepted: 03/23/2022] [Indexed: 11/16/2022] Open
Abstract
Simple Summary The telomerase enzyme adds repetitive genetic sequences to the ends of chromosomes called telomeres to prevent cellular senescence. Gain of telomerase function is one of the hallmarks of human cancer. The telomerase protein is coded by the gene TERT and increased TERT RNA levels have been associated with disease relapse in Wilms tumor, the most common kidney cancer of childhood. This study aimed to determine the mechanisms of increased TERT expression in Wilms tumor. This study found mutations in the TERT promoter, increased methylation of the TERT promoter, and genomic copy number amplifications of TERT as potential mechanisms of TERT activation. Conversely, this study found that inactivating WT1 mutation was associated with low TERT RNA levels and telomerase activity. N-MYC overexpression in Wilms tumor cells resulted in increased TERT promoter activity and TERT transcription. TERT transcription is associated with molecular and histologic subgroups in Wilms tumor and telomere-targeted therapies warrant future investigation. Abstract Increased TERT mRNA is associated with disease relapse in favorable histology Wilms tumor (WT). This study sought to understand the mechanism of increased TERT expression by determining the association between TERT and WT1 and N-MYC, two proteins important in Wilms tumor pathogenesis that have been shown to regulate TERT expression. Three out of 45 (6.7%) WTs and the corresponding patient-derived xenografts harbored canonical gain-of-function mutations in the TERT promoter. This study identified near ubiquitous hypermethylation of the TERT promoter region in WT compared to normal kidney. WTs with biallelic inactivating mutations in WT1 (7/45, 15.6%) were found to have lower TERT expression by RNA-seq and qRT-PCR and lower telomerase activity determined by the telomerase repeat amplification protocol. Anaplastic histology and increased percentage of blastema were positively correlated with higher TERT expression and telomerase activity. In vitro shRNA knockdown of WT1 resulted in decreased expression of TERT, reduced colony formation, and decreased proliferation of WiT49, an anaplastic WT cell line with wild-type WT1. CRISPR-Cas9-mediated knockout of WT1 resulted in decreased expression of telomere-related gene pathways. However, an inducible Wt1-knockout mouse model showed no relationship between Wt1 knockout and Tert expression in normal murine nephrogenesis, suggesting that WT1 and TERT are coupled in transformed cells but not in normal kidney tissues. N-MYC overexpression resulted in increased TERT promoter activity and TERT transcription. Thus, multiple mechanisms of TERT activation are involved in WT and are associated with anaplastic histology and increased blastema. This study is novel because it identifies potential mechanisms of TERT activation in Wilms tumor that could be of therapeutic interests.
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Affiliation(s)
- Carolyn M. Jablonowski
- Department of Surgery, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Mail Stop 133, Memphis, TN 38105, USA; (C.M.J.); (H.J.G.); (P.P.); (A.M.F.); (D.H.); (C.L.M.); (J.Y.); (A.M.D.)
| | - Hyea Jin Gil
- Department of Surgery, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Mail Stop 133, Memphis, TN 38105, USA; (C.M.J.); (H.J.G.); (P.P.); (A.M.F.); (D.H.); (C.L.M.); (J.Y.); (A.M.D.)
| | - Emilia M. Pinto
- Department of Pathology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (E.M.P.); (G.P.Z.)
| | - Prahalathan Pichavaram
- Department of Surgery, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Mail Stop 133, Memphis, TN 38105, USA; (C.M.J.); (H.J.G.); (P.P.); (A.M.F.); (D.H.); (C.L.M.); (J.Y.); (A.M.D.)
| | - Andrew M. Fleming
- Department of Surgery, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Mail Stop 133, Memphis, TN 38105, USA; (C.M.J.); (H.J.G.); (P.P.); (A.M.F.); (D.H.); (C.L.M.); (J.Y.); (A.M.D.)
| | - Michael R. Clay
- Department of Pathology, University of Colorado Anschutz, Aurora, CO 80045, USA;
| | - Dongli Hu
- Department of Surgery, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Mail Stop 133, Memphis, TN 38105, USA; (C.M.J.); (H.J.G.); (P.P.); (A.M.F.); (D.H.); (C.L.M.); (J.Y.); (A.M.D.)
| | - Christopher L. Morton
- Department of Surgery, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Mail Stop 133, Memphis, TN 38105, USA; (C.M.J.); (H.J.G.); (P.P.); (A.M.F.); (D.H.); (C.L.M.); (J.Y.); (A.M.D.)
| | - Shondra M. Pruett-Miller
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (S.M.P.-M.); (B.S.H.)
| | - Baranda S. Hansen
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (S.M.P.-M.); (B.S.H.)
| | - Xiang Chen
- Department of Computational Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (X.C.); (K.M.D.J.); (Y.L.); (X.M.)
| | - Karissa M. Dieseldorff Jones
- Department of Computational Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (X.C.); (K.M.D.J.); (Y.L.); (X.M.)
| | - Yanling Liu
- Department of Computational Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (X.C.); (K.M.D.J.); (Y.L.); (X.M.)
| | - Xiaotu Ma
- Department of Computational Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (X.C.); (K.M.D.J.); (Y.L.); (X.M.)
| | - Jun Yang
- Department of Surgery, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Mail Stop 133, Memphis, TN 38105, USA; (C.M.J.); (H.J.G.); (P.P.); (A.M.F.); (D.H.); (C.L.M.); (J.Y.); (A.M.D.)
| | - Andrew M. Davidoff
- Department of Surgery, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Mail Stop 133, Memphis, TN 38105, USA; (C.M.J.); (H.J.G.); (P.P.); (A.M.F.); (D.H.); (C.L.M.); (J.Y.); (A.M.D.)
- Division of Pediatric Surgery, Department of Surgery, University of Tennessee Health Science Center, Memphis, TN 38105, USA
| | - Gerard P. Zambetti
- Department of Pathology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; (E.M.P.); (G.P.Z.)
| | - Andrew J. Murphy
- Department of Surgery, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Mail Stop 133, Memphis, TN 38105, USA; (C.M.J.); (H.J.G.); (P.P.); (A.M.F.); (D.H.); (C.L.M.); (J.Y.); (A.M.D.)
- Division of Pediatric Surgery, Department of Surgery, University of Tennessee Health Science Center, Memphis, TN 38105, USA
- Correspondence:
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Caldwell JT, Jones KMD, Park H, Pinto JR, Ghosh P, Reid-Foley EC, Ulrich B, Delp MD, Behnke BJ, Muller-Delp JM. Aerobic exercise training reduces cardiac function and coronary flow-induced vasodilation in mice lacking adiponectin. Am J Physiol Heart Circ Physiol 2021; 321:H1-H14. [PMID: 33989084 DOI: 10.1152/ajpheart.00885.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We tested the hypothesis that adiponectin deficiency attenuates cardiac and coronary microvascular function and prevents exercise training-induced adaptations of the myocardium and the coronary microvasculature in adult mice. Adult wild-type (WT) or adiponectin knockout (adiponectin KO) mice underwent treadmill exercise training or remained sedentary for 8-10 wk. Systolic and diastolic functions were assessed before and after exercise training or cage confinement. Vasoreactivity of coronary resistance arteries was assessed at the end of exercise training or cage confinement. Before exercise training, ejection fraction and fractional shortening were similar in adiponectin KO and WT mice, but isovolumic contraction time was significantly lengthened in adiponectin KO mice. Exercise training increased ejection fraction (12%) and fractional shortening (20%) with no change in isovolumic contraction time in WT mice. In adiponectin KO mice, both ejection fraction (-9%) and fractional shortening (-12%) were reduced after exercise training and these decreases were coupled to a further increase in isovolumic contraction time (20%). In sedentary mice, endothelium-dependent dilation to flow was higher in arterioles from adiponectin KO mice as compared with WT mice. Exercise training enhanced dilation to flow in WT mice but decreased flow-induced dilation in adiponectin KO mice. These data suggest that compensatory mechanisms contribute to the maintenance of cardiac and coronary microvascular function in sedentary mice lacking adiponectin; however, in the absence of adiponectin, cardiac and coronary microvascular adaptations to exercise training are compromised.NEW & NOTEWORTHY We report that compensatory mechanisms contribute to the maintenance of cardiac and coronary microvascular function in sedentary mice in which adiponectin has been deleted; however, when mice lacking adiponectin are subjected to the physiological stress of exercise training, beneficial coronary microvascular and cardiac adaptations are compromised or absent.
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Affiliation(s)
- Jacob T Caldwell
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida
| | | | - Hyerim Park
- Department of Nutrition, Food and Exercise Science, Florida State University, Tallahassee, Florida
| | - Jose R Pinto
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida
| | - Payal Ghosh
- Department of Nutrition, Food and Exercise Science, Florida State University, Tallahassee, Florida
| | - Emily C Reid-Foley
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida
| | - Brody Ulrich
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida
| | - Michael D Delp
- Department of Nutrition, Food and Exercise Science, Florida State University, Tallahassee, Florida
| | - Brad J Behnke
- Department of Kinesiology, Johnson Cancer Research Center, Kansas State University, Manhattan, Kansas
| | - Judy M Muller-Delp
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida
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Marques MA, Landim-Vieira M, Moraes AH, Sun B, Johnston JR, Dieseldorff Jones KM, Cino EA, Parvatiyar MS, Valera IC, Silva JL, Galkin VE, Chase PB, Kekenes-Huskey PM, de Oliveira GAP, Pinto JR. Anomalous structural dynamics of minimally frustrated residues in cardiac troponin C triggers hypertrophic cardiomyopathy. Chem Sci 2021; 12:7308-7323. [PMID: 34163821 PMCID: PMC8171346 DOI: 10.1039/d1sc01886h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 04/11/2021] [Indexed: 12/13/2022] Open
Abstract
Cardiac TnC (cTnC) is highly conserved among mammals, and genetic variants can result in disease by perturbing Ca2+-regulation of myocardial contraction. Here, we report the molecular basis of a human mutation in cTnC's αD-helix (TNNC1-p.C84Y) that impacts conformational dynamics of the D/E central-linker and sampling of discrete states in the N-domain, favoring the "primed" state associated with Ca2+ binding. We demonstrate cTnC's αD-helix normally functions as a central hub that controls minimally frustrated interactions, maintaining evolutionarily conserved rigidity of the N-domain. αD-helix perturbation remotely alters conformational dynamics of the N-domain, compromising its structural rigidity. Transgenic mice carrying this cTnC mutation exhibit altered dynamics of sarcomere function and hypertrophic cardiomyopathy. Together, our data suggest that disruption of evolutionary conserved molecular frustration networks by a myofilament protein mutation may ultimately compromise contractile performance and trigger hypertrophic cardiomyopathy.
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Affiliation(s)
- Mayra A Marques
- Institute of Medical Biochemistry Leopoldo de Meis, National Institute of Structural Biology and Bioimaging, National Center of Nuclear Magnetic Resonance Jiri Jonas, Federal University of Rio de Janeiro 373 Carlos Chagas Filho Av, Room: E-10 Rio de Janeiro RJ 21941-902 Brazil +55-21-3938-6756
| | - Maicon Landim-Vieira
- Department of Biomedical Sciences, Florida State University, College of Medicine 1115 West Call Street, Room: 1370 (lab) - 1350-H (office) Tallahassee FL 32306 USA +1-850-645-0016
| | - Adolfo H Moraes
- Department of Chemistry, Federal University of Minas Gerais Belo Horizonte MG Brazil
| | - Bin Sun
- Department of Cell and Molecular Physiology, Loyola University Chicago Maywood IL USA
| | - Jamie R Johnston
- Department of Biomedical Sciences, Florida State University, College of Medicine 1115 West Call Street, Room: 1370 (lab) - 1350-H (office) Tallahassee FL 32306 USA +1-850-645-0016
| | - Karissa M Dieseldorff Jones
- Department of Biomedical Sciences, Florida State University, College of Medicine 1115 West Call Street, Room: 1370 (lab) - 1350-H (office) Tallahassee FL 32306 USA +1-850-645-0016
| | - Elio A Cino
- Department of Biochemistry and Immunology, Federal University of Minas Gerais Belo Horizonte MG Brazil
| | - Michelle S Parvatiyar
- Department of Nutrition, Food and Exercise Sciences, Florida State University Tallahassee FL USA
| | - Isela C Valera
- Department of Nutrition, Food and Exercise Sciences, Florida State University Tallahassee FL USA
| | - Jerson L Silva
- Institute of Medical Biochemistry Leopoldo de Meis, National Institute of Structural Biology and Bioimaging, National Center of Nuclear Magnetic Resonance Jiri Jonas, Federal University of Rio de Janeiro 373 Carlos Chagas Filho Av, Room: E-10 Rio de Janeiro RJ 21941-902 Brazil +55-21-3938-6756
| | - Vitold E Galkin
- Department of Physiological Sciences, Eastern Virginia Medical School Norfolk VA USA
| | - P Bryant Chase
- Department of Biological Science, Florida State University Tallahassee FL USA
| | | | - Guilherme A P de Oliveira
- Institute of Medical Biochemistry Leopoldo de Meis, National Institute of Structural Biology and Bioimaging, National Center of Nuclear Magnetic Resonance Jiri Jonas, Federal University of Rio de Janeiro 373 Carlos Chagas Filho Av, Room: E-10 Rio de Janeiro RJ 21941-902 Brazil +55-21-3938-6756
| | - Jose Renato Pinto
- Department of Biomedical Sciences, Florida State University, College of Medicine 1115 West Call Street, Room: 1370 (lab) - 1350-H (office) Tallahassee FL 32306 USA +1-850-645-0016
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Dieseldorff Jones KM, Vied C, Valera IC, Chase PB, Parvatiyar MS, Pinto JR. Sexual dimorphism in cardiac transcriptome associated with a troponin C murine model of hypertrophic cardiomyopathy. Physiol Rep 2020; 8:e14396. [PMID: 32189431 PMCID: PMC7081104 DOI: 10.14814/phy2.14396] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 02/13/2020] [Accepted: 02/16/2020] [Indexed: 12/12/2022] Open
Abstract
Heart disease remains the number one killer of women in the US. Nonetheless, studies in women and female animal models continue to be underrepresented in cardiac research. Hypertrophic cardiomyopathy (HCM), the most commonly inherited cardiac disorder, has been tied to sarcomeric protein variants in both sexes. Among the susceptible genes, TNNC1-encoding cardiac troponin C (cTnC)-causes a substantial HCM phenotype in mice. Mice bearing an HCM-associated cTnC-A8V point mutation exhibited a significant decrease in stroke volume and left ventricular diameter and volume. Importantly, isovolumetric contraction time was significantly higher for female HCM mice. We utilized a transcriptomic approach to investigate the basis underlying the sexual dimorphism observed in the cardiac physiology of adult male and female HCM mice. RNA sequencing revealed several altered canonical pathways within the HCM mice versus WT groups including an increase in eukaryotic initiation factor 2 signaling, integrin-linked kinase signaling, actin nucleation by actin-related protein-Wiskott-Aldrich syndrome family protein complex, regulation of actin-based motility by Rho kinase, vitamin D receptor/retinoid X receptor activation, and glutathione redox reaction pathways. In contrast, valine degradation, tricarboxylic acid cycle II, methionine degradation, and inositol phosphate compound pathways were notably down-regulated in HCM mice. These down-regulated pathways may be reduced in response to altered energetics in the hypertrophied hearts and may represent conservation of energy as the heart is compensating to meet increased contractile demands. HCM male versus female mice followed similar trends of the canonical pathways altered between HCM and WT. In addition, seven of the differentially expressed genes in both WT and HCM male versus female comparisons swapped directions in fold-change between the sexes. These findings suggest a sexually-dimorphic HCM phenotype due to a sarcomeric mutation and pinpoint several key targetable pathways and genes that may provide the means to alleviate the more severe decline in female cardiac function.
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Affiliation(s)
| | - Cynthia Vied
- Translational Science LaboratoryCollege of MedicineFlorida State UniversityTallahasseeFLUSA
| | - Isela C. Valera
- Department of Nutrition, Food and Exercise SciencesFlorida State UniversityTallahasseeFLUSA
| | - P. Bryant Chase
- Department of Biological ScienceFlorida State UniversityTallahasseeFLUSA
| | - Michelle S. Parvatiyar
- Department of Nutrition, Food and Exercise SciencesFlorida State UniversityTallahasseeFLUSA
| | - Jose R. Pinto
- Department of Biomedical SciencesCollege of MedicineFlorida State UniversityTallahasseeFLUSA
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Dieseldorff Jones KM, Vied C, Valera IC, Chase PB, Parvatiyar MS, Pinto JR. Sex Differences in Regulating the Cardiac Transcriptome within a Murine Model for Hypertrophic Cardiomyopathy. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.3217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Parvatiyar MS, Brownstein AJ, Kanashiro-Takeuchi RM, Collado JR, Dieseldorff Jones KM, Gopal J, Hammond KG, Marshall JL, Ferrel A, Beedle AM, Chamberlain JS, Renato Pinto J, Crosbie RH. Stabilization of the cardiac sarcolemma by sarcospan rescues DMD-associated cardiomyopathy. JCI Insight 2019; 5:123855. [PMID: 31039133 PMCID: PMC6629091 DOI: 10.1172/jci.insight.123855] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 04/23/2019] [Indexed: 02/02/2023] Open
Abstract
In the current preclinical study, we demonstrate the therapeutic potential of sarcospan (SSPN) overexpression to alleviate cardiomyopathy associated with Duchenne muscular dystrophy (DMD) utilizing dystrophin-deficient mdx mice with utrophin haploinsufficiency that more accurately represent the severe disease course of human DMD. SSPN interacts with dystrophin, the DMD disease gene product, and its autosomal paralog utrophin, which is upregulated in DMD as a partial compensatory mechanism. SSPN transgenic mice have enhanced abundance of fully glycosylated α-dystroglycan, which may further protect dystrophin-deficient cardiac membranes. Baseline echocardiography reveals SSPN improves systolic function and hypertrophic indices in mdx and mdx:utr-heterozygous mice. Assessment of SSPN transgenic mdx mice by hemodynamic pressure-volume methods highlights enhanced systolic performance compared to mdx controls. SSPN restores cardiac sarcolemma stability, the primary defect in DMD disease, reduces fibrotic response and improves contractile function. We demonstrate that SSPN ameliorates more advanced cardiac disease in the context of diminished sarcolemma expression of utrophin and β1D integrin that mitigate disease severity and partially restores responsiveness to β-adrenergic stimulation. Overall, our current and previous findings suggest SSPN overexpression in DMD mouse models positively impacts skeletal, pulmonary and cardiac performance by addressing the stability of proteins at the sarcolemma that protect the heart from injury, supporting SSPN and membrane stabilization as a therapeutic target for DMD.
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Affiliation(s)
- Michelle S. Parvatiyar
- Department of Integrative Biology & Physiology and
- Center for Duchenne Muscular Dystrophy, UCLA, Los Angeles, California, USA
| | - Alexandra J. Brownstein
- Department of Integrative Biology & Physiology and
- Center for Duchenne Muscular Dystrophy, UCLA, Los Angeles, California, USA
| | - Rosemeire M. Kanashiro-Takeuchi
- Interdisciplinary Stem Cell Institute, University of Miami, Florida, USA
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, Florida, USA
| | | | | | - Jay Gopal
- Department of Integrative Biology & Physiology and
| | - Katherine G. Hammond
- Department of Integrative Biology & Physiology and
- Center for Duchenne Muscular Dystrophy, UCLA, Los Angeles, California, USA
| | - Jamie L. Marshall
- Department of Integrative Biology & Physiology and
- Center for Duchenne Muscular Dystrophy, UCLA, Los Angeles, California, USA
| | - Abel Ferrel
- Department of Integrative Biology & Physiology and
| | - Aaron M. Beedle
- Department of Pharmaceutical Sciences, Binghamton University State University of New York, Binghamton, New York, USA
| | | | - Jose Renato Pinto
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida, USA
| | - Rachelle H. Crosbie
- Department of Integrative Biology & Physiology and
- Center for Duchenne Muscular Dystrophy, UCLA, Los Angeles, California, USA
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- Molecular Biology Institute, UCLA, Los Angeles, California, USA
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Dieseldorff Jones KM, Koh Y, Weller RS, Turna RS, Ahmad F, Huke S, Knollmann BC, Pinto JR, Hwang HS. Pathogenic troponin T mutants with opposing effects on myofilament Ca 2+ sensitivity attenuate cardiomyopathy phenotypes in mice. Arch Biochem Biophys 2018; 661:125-131. [PMID: 30445044 DOI: 10.1016/j.abb.2018.11.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 08/28/2018] [Accepted: 11/08/2018] [Indexed: 01/14/2023]
Abstract
Mutations in cardiac troponin T (TnT) associated with hypertrophic cardiomyopathy generally lead to an increase in the Ca2+ sensitivity of contraction and susceptibility to arrhythmias. In contrast, TnT mutations linked to dilated cardiomyopathy decrease the Ca2+ sensitivity of contraction. Here we tested the hypothesis that two TnT disease mutations with opposite effects on myofilament Ca2+ sensitivity can attenuate each other's phenotype. We crossed transgenic mice expressing the HCM TnT-I79N mutation (I79N) with a DCM knock-in mouse model carrying the heterozygous TnT-R141W mutation (HET). The results of the Ca2+ sensitivity in skinned cardiac muscle preparations ranked from highest to lowest were as follow: I79N > I79N/HET > NTg > HET. Echocardiographic measurements revealed an improvement in hemodynamic parameters in I79N/HET compared to I79N and normalization of left ventricular dimensions and volumes compared to both I79N and HET. Ex vivo testing showed that the I79N/HET mouse hearts had reduced arrhythmia susceptibility compared to I79N mice. These results suggest that two disease mutations in TnT that have opposite effects on the myofilament Ca2+ sensitivity can paradoxically ameliorate each other's disease phenotype. Normalizing myofilament Ca2+ sensitivity may be a promising new treatment approach for a variety of diseases.
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Affiliation(s)
| | - Yeojung Koh
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, USA
| | - Rebecca S Weller
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Rajdeep S Turna
- Biomedical Sciences, Florida State University, Tallahassee, FL, USA
| | - Ferhaan Ahmad
- Department of Internal Medicine University of Iowa, Iowa City, IA, USA
| | - Sabine Huke
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA; Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Björn C Knollmann
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA
| | | | - Hyun Seok Hwang
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, USA.
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Veltri T, Landim-Vieira M, Parvatiyar MS, Gonzalez-Martinez D, Dieseldorff Jones KM, Michell CA, Dweck D, Landstrom AP, Chase PB, Pinto JR. Hypertrophic Cardiomyopathy Cardiac Troponin C Mutations Differentially Affect Slow Skeletal and Cardiac Muscle Regulation. Front Physiol 2017; 8:221. [PMID: 28473771 PMCID: PMC5397416 DOI: 10.3389/fphys.2017.00221] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 03/27/2017] [Indexed: 12/22/2022] Open
Abstract
Mutations in TNNC1—the gene encoding cardiac troponin C (cTnC)—that have been associated with hypertrophic cardiomyopathy (HCM) and cardiac dysfunction may also affect Ca2+-regulation and function of slow skeletal muscle since the same gene is expressed in both cardiac and slow skeletal muscle. Therefore, we reconstituted rabbit soleus fibers and bovine masseter myofibrils with mutant cTnCs (A8V, C84Y, E134D, and D145E) associated with HCM to investigate their effects on contractile force and ATPase rates, respectively. Previously, we showed that these HCM cTnC mutants, except for E134D, increased the Ca2+ sensitivity of force development in cardiac preparations. In the current study, an increase in Ca2+ sensitivity of isometric force was only observed for the C84Y mutant when reconstituted in soleus fibers. Incorporation of cTnC C84Y in bovine masseter myofibrils reduced the ATPase activity at saturating [Ca2+], whereas, incorporation of cTnC D145E increased the ATPase activity at inhibiting and saturating [Ca2+]. We also tested whether reconstitution of cardiac fibers with troponin complexes containing the cTnC mutants and slow skeletal troponin I (ssTnI) could emulate the slow skeletal functional phenotype. Reconstitution of cardiac fibers with troponin complexes containing ssTnI attenuated the Ca2+ sensitization of isometric force when cTnC A8V and D145E were present; however, it was enhanced for C84Y. In summary, although the A8V and D145E mutants are present in both muscle types, their functional phenotype is more prominent in cardiac muscle than in slow skeletal muscle, which has implications for the protein-protein interactions within the troponin complex. The C84Y mutant warrants further investigation since it drastically alters the properties of both muscle types and may account for the earlier clinical onset in the proband.
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Affiliation(s)
- Tiago Veltri
- Department of Biomedical Sciences, Florida State University College of MedicineTallahassee, FL, USA
| | - Maicon Landim-Vieira
- Department of Biomedical Sciences, Florida State University College of MedicineTallahassee, FL, USA
| | - Michelle S Parvatiyar
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of MedicineMiami, FL, USA
| | - David Gonzalez-Martinez
- Department of Biomedical Sciences, Florida State University College of MedicineTallahassee, FL, USA
| | | | - Clara A Michell
- Department of Biomedical Sciences, Florida State University College of MedicineTallahassee, FL, USA
| | - David Dweck
- Department of Biomedical Sciences, Florida State University College of MedicineTallahassee, FL, USA
| | - Andrew P Landstrom
- Section of Pediatric Cardiology, Department of Pediatrics, Baylor College of MedicineHouston, TX, USA
| | - P Bryant Chase
- Department of Biological Science, Florida State UniversityTallahassee, FL, USA
| | - Jose R Pinto
- Department of Biomedical Sciences, Florida State University College of MedicineTallahassee, FL, USA
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